Abstract

A large number of different models for concurrent object-oriented programming have been proposed. None of this models have received widespread acceptance. In this paper the Simula model of quasi-parallel execution is extended to include concurrency and synchronization. Active objects may execute concurrently and access shared objects without synchronization. Synchronization may be obtained by means of semaphores. In order to avoid explicit low-level manipulation of semaphores, it is possible to build high-level concurrency abstractions that encapsulates and hide the details of the semaphores. A class library may then include abstractions corresponding to commonly used mechanisms like monitor and rendezvous. When these mechanisms are not adequate, it is possible to define new concurrency abstractions. This approach to concurrent object-oriented programming makes it possible to use many different concurrency abstractions within the same language. It is also possible to some ...

Citations

1008	Actors: a model of concurrent computation in distributed systems - Agha - 1986
98	Inheritance and subtyping in a parallel object-oriented language - America - 1987
7	Hierarchical program structures, Structured Programming - Dahl, Hoare - 1972
3	der Linden: A parallel object-oriented language with inheritance and subtyping - America, van - 1990
1	C++ has a form of nested classes, but a nested class cannot refer to variables in the enclosing class. Only local variables and global variables can be referred within a class - Briot, A - 1987